package cn.chiship.bs.api.core.util;

import cn.chiship.sdk.core.util.Base64Util;
import org.springframework.web.multipart.MultipartFile;

import java.io.*;
import java.util.Random;

/**
 * base64转为multipartFile工具类
 *
 * @author lijian
 */

public class Base64ToMultipartFile implements MultipartFile {
    private Random random = new Random();

    private final byte[] imgContent;
    private final String header;

    public Base64ToMultipartFile(byte[] imgContent, String header) {
        this.imgContent = imgContent;
        this.header = header.split(";")[0];
    }

    @Override
    public String getName() {
        return System.currentTimeMillis() + Math.random() + "." + header.split("/")[1];
    }

    @Override
    public String getOriginalFilename() {
        return System.currentTimeMillis() + random.nextInt() * 10000 + "." + header.split("/")[1];
    }

    @Override
    public String getContentType() {
        return header.split(":")[1];
    }

    @Override
    public boolean isEmpty() {
        return imgContent == null || imgContent.length == 0;
    }

    @Override
    public long getSize() {
        return imgContent.length;
    }

    @Override
    public byte[] getBytes() throws IOException {
        return imgContent;
    }

    @Override
    public InputStream getInputStream() {
        return new ByteArrayInputStream(imgContent);
    }

    @Override
    public void transferTo(File dest) throws IOException, IllegalStateException {
        new FileOutputStream(dest).write(imgContent);
    }

    /**
     * base64转multipartFile
     */
    public static MultipartFile base64Convert(String base64) {

        String[] baseStr = base64.split(",");
        byte[] b = Base64Util.decode(baseStr[1]);
        for (int i = 0; i < b.length; ++i) {
            if (b[i] < 0) {
                b[i] += 256;
            }
        }
        return new Base64ToMultipartFile(b, baseStr[0]);
    }
}
